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Figure 2 shows the structure of a molecule of dichloroethene - Edexcel - GCSE Chemistry - Question 4 - 2020 - Paper 1
Question 4
Figure 2 shows the structure of a molecule of dichloroethene. (a) (i) Describe how dichloroethene monomers form a polymer. (ii) Which of these represents the struc... show full transcript
Worked Solution & Example Answer:Figure 2 shows the structure of a molecule of dichloroethene - Edexcel - GCSE Chemistry - Question 4 - 2020 - Paper 1
Step 1
Describe how dichloroethene monomers form a polymer.
Answer
Dichloroethene monomers can undergo a process called polymerization.
- Initiation: The double bond in the dichloroethene allows for the formation of free radicals when subjected to heat or a catalyst.
- Propagation: The free radicals react with other dichloroethene molecules, causing the double bonds to open up and bond with adjacent monomers, forming long chains called polymers.
- Termination: The reaction continues until chain growth stops, usually due to a lack of monomers or the reaction being terminated by other means.
Step 2
Which of these represents the structure of the polymer formed from the monomer in Figure 2?
Answer
To identify the correct structure of the polymer from the options provided:
- The polymer should consist of repeating units of dichloroethene with single bonds instead of double bonds, reflecting the saturation of the polymer chain.
- The correct answer is likely to show multiple -C-C- bonds that connect without any double bonds, retaining the chlorinated substituents in the backbone.